Electrolyte Solution for Rechargeable Lithium Battery and Rechargeable Lithium Battery Including the Same

This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2024-0051944, filed on Apr. 18, 2024, the entire contents of which are hereby incorporated by reference.

Examples of the present disclosure relates to an electrolyte solution for a rechargeable lithium battery and a rechargeable lithium battery including the electrolyte solution.

The increased use of battery-powered electronics such as, e.g., mobile phones, laptop computers, electric vehicles, and the like, has increased demand for rechargeable batteries provided with high energy density and high capacity.

Rechargeable lithium batteries typically include a positive electrode and a negative electrode, each of the positive electrode and the negative electrode including an active material that allows intercalation and deintercalation of lithium ions, and an electrolyte solution. The rechargeable lithium battery generates electrical energy from redox reactions that take place as lithium ions are intercalated into or deintercalated from the positive electrode and the negative electrode.

In an example, in which a lithium salt is dissolved in a non-aqueous organic solvent and constitutes an electrolyte of the rechargeable lithium batteries. The rechargeable lithium batteries exhibit characteristics thereof through complex reactions between the positive electrode and the electrolyte, and between the negative electrode and the electrolyte. Thus, the use of an appropriate electrolyte is a compelling variable in improving performance of the rechargeable lithium batteries.

Examples of present disclosure include an electrolyte solution for a rechargeable lithium battery, the electrolyte solution having improved lifetime characteristics and stability at high temperatures.

Examples of the present disclosure also include a rechargeable lithium battery including the electrolyte solution.

An example embodiment of the present disclosure includes an electrolyte solution for a rechargeable lithium battery, the electrolyte solution including at least a non-aqueous organic solvent, a lithium salt, and an additive represented by Formula 1 below.

In Formula 1 above,

In an example embodiment of the present disclosure, a rechargeable lithium battery includes a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and an electrolyte solution. The electrolyte solution includes a non-aqueous organic solvent, a lithium salt, and an additive represented by Formula 1 described above.

In an example embodiment of the present disclosure, an electrolyte additive compound for a rechargeable lithium battery is represented by Formula 1-1 below:

In order to sufficiently understand the configuration and effects of the present disclosure, example embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted, however, that the present disclosure is not limited to the following example embodiments, and may be implemented in various forms and variously modified. The example embodiments herein are provided so that the present disclosure is thorough and complete, and fully conveys the scope of the present disclosure to those skilled in the art.

Herein, it will be understood that when a component is referred to as being on another component, the component may be directly on another component, or an intervening third component may be present. In addition, in the drawings, thicknesses of components are exaggerated for effectively describing technical contents. Like reference numerals refer to like elements throughout.

Unless otherwise specified herein, the expression of singular form may include the expression of plural form. In addition, unless otherwise specified, the phrase “A or B” may indicate “A but not B,” “B but not A,” or “A and B.” The terms “comprises” and/or “comprising” used herein do not exclude the presence or addition of one or more other components.

As used herein, the term “combination thereof” may refer to a mixture, a stack, a composite, a copolymer, an alloy, a blend, or a reaction product.

Herein, unless otherwise defined, “substitution” indicates that at least one hydrogen in a substituent or compound is substituted with deuterium, a halogen group, a hydroxyl group, an amino group, a C1 to C30 amine group, a nitro group, a C1 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C20 alkoxy group, a C1 to C10 fluoroalkyl group, a cyano group, or a combination thereof.

Specifically, the “substitution” may indicate that at least one hydrogen in a substituent or compound is substituted with deuterium, a halogen group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C10 fluoroalkyl group, or a cyano group. For example, the “substitution” may indicate that at least one hydrogen in a substituent or compound is substituted with deuterium, a halogen group, a C1 to C20 alkyl group, a C6 to C30 aryl group, a C1 to C10 fluoroalkyl group, or a cyano group. In addition, the “substitution” may indicate that at least one hydrogen in a substituent or compound is substituted with deuterium, a halogen group, a C1 to C5 alkyl group, a C6 to C18 aryl group, a C1 to C5 fluoroalkyl group, or a cyano group. For example, the “substitution” may indicate that at least one hydrogen in a substituent or compound is substituted with deuterium, a cyano group, a halogen group, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a biphenyl group, a terphenyl group, a trifluoromethyl group, or a naphthyl group.

When the terms “about” or “substantially” are used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ±10% around the stated numerical value. When ranges are specified, the range includes all values therebetween such as increments of 0.1%.

is a cross-sectional view of a rechargeable lithium battery according to example embodiments of the present disclosure. Referring to, the rechargeable lithium battery may include a positive electrode, a negative electrode, a separator, and an electrolyte solution ELL.

The positive electrodeand the negative electrodemay be spaced apart from each other by the separator. The separatormay be between the positive electrodeand the negative electrode. The positive electrode, the negative electrodeand the separatormay be in contact with the electrolyte solution ELL. The positive electrode, the negative electrodeand the separatormay be impregnated in the electrolyte solution ELL.

The electrolyte solution ELL may constitute a medium for transferring lithium ions between the positive electrodeand the negative electrode. In the electrolyte solution ELL, the lithium ions may move through the separatortoward the positive electrodeor the negative electrode.

The positive electrodefor a rechargeable lithium battery may include a current collector COL1 and a positive electrode active material layer AML1 on the current collector. The positive electrode active material layer AML1 may include a positive electrode active material, and may further include a binder and/or a conductive material (e.g., an electrically conductive material).

For example, the positive electrodemay further include an additive that can constitute a sacrificial positive electrode.

An amount of the positive electrode active material may be about 90 wt % to about 99.5 wt % based on 100 wt % of the positive electrode active material layer AML1. Amounts of the binder and the conductive material may be about 0.5 wt % to about 5 wt %, respectively, based on 100 wt % of the positive electrode active material layer AML1.

The binder is configured to sufficiently attach the positive electrode active material particles to each other and also to sufficiently attach the positive electrode active material to the current collector COLL. Examples of the binder may include at least one of polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinylchloride, carboxylated polyvinylchloride, polyvinylfluoride, a polymer including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, a styrene-butadiene rubber, a (meth)acrylated styrene-butadiene rubber, an epoxy resin, a (meth)acrylic resin, a polyester resin, nylon, and the like, as non-limiting examples.

The conductive material may impart conductivity (e.g., electrical conductivity) to the electrode. Any material that does not cause chemical change (e.g., that does not cause an undesirable chemical change in the rechargeable lithium battery) and that conducts electrons can be used in the battery. Examples of the conductive material may include at least one of a carbon-based material such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, a carbon fiber, a carbon nanofiber, and carbon nanotube; a metal-based material containing at least one of copper, nickel, aluminum, silver, and the like, in a form of a metal powder or a metal fiber; a conductive polymer such as a polyphenylene derivative; or a mixture thereof.

Al may be used as the current collector COL1, but is not limited thereto.

The positive electrode active material may include a compound (lithiated intercalation compound) that is capable of intercalating and deintercalating lithium. For example, at least one of a composite oxide of lithium and a metal including at least one of cobalt, manganese, nickel, and combinations thereof may be used.

The composite oxide may be or include a lithium transition metal composite oxide. Examples of the composite oxide may include at least one of lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

As an example, the following compounds represented by any one or more of the following Chemical Formulas may be used. LiAXOD(0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); LiMnXOD(0.90≤a≤1.8, 0≤b≤0.5, and O≤c≤0.05); LiNiCoXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); LiNiMnXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); LiNiCoLGO(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, O≤d≤0.5, and 0≤e≤0.1); LiNiGO(0.90≤a≤1.8 and 0.001≤b≤0.1); LiCoGO(0.90≤a≤1.8 and 0.001≤b≤0.1); LiMnGO(0.90≤a≤1.8 and 0.001≤b≤0.1); LiMnGO(0.90≤a≤1.8 and 0.001≤b≤0.1); LiMnGPO(0.90≤a≤1.8 and 0≤g≤0.5); LiFe(PO)(0≤f≤2); or LiFePO(0.90≤a≤1.8).

In the above Chemical Formulas, A is or includes at least one of Ni, Co, Mn, or a combination thereof; X is or includes at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is or includes at least one of O, F, S, P, or a combination thereof; G is or includes at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and Lis or includes at least one of Mn, Al, or a combination thereof.

The positive electrode active material may be or include, for example, a high nickel-based positive electrode active material having a nickel content that is greater than or equal to about 80 mol %, greater than or equal to about 85 mol %, greater than or equal to about 90 mol %, greater than or equal to about 91 mol %, or greater than or equal to about 94 mol % and less than or equal to about 99 mol % based on 100 mol % of the metal excluding lithium in the lithium transition metal composite oxide. The high-nickel-based positive electrode active material may be capable of realizing high capacity and can be applied to a high-capacity, high-density rechargeable lithium battery.

The negative electrodefor a rechargeable lithium battery may include a current collector COL2 and a negative electrode active material layer AML2 on the current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material, and may further include a binder and/or a conductive material (e.g., an electrically conductive material).

For example, the negative electrode active material layer AML2 may include about 90 wt % to about 99 wt % of the negative electrode active material, about 0.5 wt % to about 5 wt % of the binder, and about 0 wt % to about 5 wt % of the conductive material.

The binder may be configured to sufficiently attach the negative electrode active material particles to each other and also to sufficiently attach the negative electrode active material to the current collector COL2. The binder may include a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

The non-aqueous binder may include at least one of polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, poly amideimide, polyimide, or a combination thereof.

The aqueous binder may include at least one of a styrene-butadiene rubber, a (meth)acrylated styrene-butadiene rubber, a (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, a butyl rubber, a fluoro rubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrine, polyphosphazene, poly(meth)acrylonitrile, an ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, a polyester resin, a (meth)acrylic resin, a phenol resin, an epoxy resins, polyvinyl alcohol, and a combination thereof.

When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may include at least one of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may include at least one of Na, K, or Li.

The dry binder may be or include a polymer material that is capable of being fibrous. For example, the dry binder may be or include polytetrafluoroethylene, polyvinylidene fluoride, a polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

The conductive material may be used to impart conductivity (e.g., electrical conductivity) to the electrode. Any material that does not cause chemical change (e.g., that does not cause an undesirable chemical change in the rechargeable lithium battery) and that conducts electrons can be used in the battery. Non-limiting examples thereof may include a carbon-based material such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, a carbon fiber, a carbon nanofiber, and a carbon nanotube; a metal-based material including at least one of copper, nickel, aluminum, silver, etc. in a form of a metal powder or a metal fiber; a conductive polymer such as a polyphenylene derivative; or a mixture thereof.

The negative current collector COL2 may include at least one of a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

The negative electrode active material may include a material that reversibly intercalates/deintercalates lithium ions, a lithium metal, a lithium metal alloy, a material capable of doping/dedoping lithium, or a transition metal oxide.

The material that reversibly intercalates/deintercalates lithium ions may include a carbon-based negative electrode active material, such as, for example. crystalline carbon, amorphous carbon or a combination thereof. The crystalline carbon may be graphite such as non-shaped, sheet-shaped, flake-shaped, sphere-shaped, or fiber-shaped natural graphite or artificial graphite. The amorphous carbon may be a soft carbon, a hard carbon, a mesophase pitch carbonization product, calcined coke, and the like.

The lithium metal alloy includes an alloy of lithium and a metal including at least one of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

The material capable of doping/dedoping lithium may be or include a Si-based negative electrode active material or a Sn-based negative electrode active material. The Si-based negative electrode active material may include at least one of silicon, a silicon-carbon composite, SiOx (0<x<2), a Si-Q alloy (where Q includes at least one of an alkali metal, an alkaline-earth metal, a Group 13 element, a Group 14 element (excluding Si), a Group 15 element, a Group 16 element, a transition metal, a rare earth element, and a combination thereof). The Sn-based negative electrode active material may include Sn, SnO, a Sn-based alloy, or a combination thereof.

The silicon-carbon composite may be or include a composite of silicon and amorphous carbon. According to an example embodiment, the silicon-carbon composite may be in the form of, or include, silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite may include a secondary particle (core) in which primary silicon particles are assembled, and an amorphous carbon coating layer (shell) on the surface of the secondary particle. The amorphous carbon may also be between the primary silicon particles, and, for example, the primary silicon particles may be coated with the amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core including crystalline carbon, and silicon particles and an amorphous carbon coating layer on a surface of the core.

The Si-based negative electrode active material or the Sn-based negative electrode active material may be combined with a carbon-based negative electrode active material.